Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Genoni failure solution

Henry
Henry Member Posts: 996
We have noticed a number of genoni heat exchanger failures in apartment blocks that have had to drain the system for repairs. The fresh water causes corrosion and iron oxide sludge (manganite). For up to 1 million BTU, it is a 1 inch bypass system with a Dirtmag and a 20 inch 5 micron bag filter plus a flow meter. Up to 2 million BTU it is a 2 inch Dirtmag and a 40 inch 5 micron bag filter plus a flow meter. The flow rate for the 1 inch is 10 GPM and an UP15-42 is satisfactory. The 2 inch is at 45 GPM using an UPS26-150. The enclosed sketch shows an error by our tech, it is not 5 GPM for the 1 inch. It is in French as most of our plumbers are French speaking. The enclosed pictures show a sample of boiler water that was magnetised. The iron particles fell to the magnet. The yellow water was the same system after two months of bypass filtration. It is a relatively inexpensive insurance for the boilers.




Comments

  • SuperTech
    SuperTech Member Posts: 2,120
    The Dirtmag is a great product, I'm always surprised at how much magnetite gets blown out after I remove the magnet.
    How often do you need to replace the five micron bag filter?
  • Henry
    Henry Member Posts: 996
    The first one after a week, then two weeks. The janitor empties the dirtmag daily.
    SuperTech
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Is there a differential pressure monitor or gauge to determine when the bag needs to be changed?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • hot_rod
    hot_rod Member Posts: 21,835

    Is there a differential pressure monitor or gauge to determine when the bag needs to be changed?

    good thought, a pressure gauge on the filter would be an indicator, like a pool filter typically uses.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Canucker
  • Steamhead
    Steamhead Member Posts: 16,718
    The best solution is not to use a boiler with a Giannoni heat exchanger in the first place. Then, all these band-aids aren't needed.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    rwhtg
  • hot_rod
    hot_rod Member Posts: 21,835
    Nothing at all wrong with Sermeta HX as long as they are pumped properly, have good water quality and adjusted and cleaned on the burner side. Mounted improperly in plastic enclosures didn't help their longevity :)
    Still plenty being used in single and stacked versions. Some long experienced wholesalers tell me fire tube style are failing as if not more often than the Sermeta style.
    https://sermeta.com/en-us/
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Henry
    Henry Member Posts: 996
    There is a flow meter (débitmetre) to tell the user when to replace the filter or to purge the dirtmag. We have Genoni/Sermeta boilers running for over 12 years with relatively low maintenance. But if one not installed properly with the right pipe size or pump, it can fail within 5 years. A lot of installers look at the boiler connection size and not the required flow rate size. It is like connecting a 500,000 BTU flat plate heat exchanger that has 1 inch connection and use 1 inch to the boiler! 500,000 BTU requires 2 inch! Even if one sizes everything right but there are frequent emptying of the system to repair leaks, the boilers will pack up due to the fresh O2 and water with sludge. The system that I have shown is for existing installations. New installations can have a Dirtmag of the proper size instead of a Y strainer.